Wayne,
I have been using DVmatte Pro for a couple of years. It is outstanding. I use it for keying and sometimes to generate mattes to use in AE. It will seamlessly key even badly lit greenscreens. And while it was designed for use with DV footage, it works just great with uncompressed. I have no experience with it and HD material however.
We had a pretty good discussion on it last year here, Marco Solario (I think) swears by Ultimatte, but he agreed that DMP is vastly superior to FCP keyer, and it costs about a fifth the price of Ultimatte.